1. Field of the Invention
The present invention relates to improvements in a hydraulic motor for coupling to a reciprocating piston type of pump. Such motors and pistons generally are applied to a variety of uses, for example to supply slurries of paint or other coating compositions to spray heads for an airless paint sprayer.
2. Description of the Prior Art
Hydraulic motors for use with reciprocating pistons for airless paint sprayers have been used in the past. An illustration of such a hydraulic motor is manufactured by Speedflo. While such a motor is hydraulically actuated and coupled to a piston the internal reciprocating motor piston within the motor employs a single stop means that causes a binding of the parts.
The Speedflo hydraulic motor utilizes a single spring loaded ball that moves horizontally into detents or grooves in the spool. Such construction has the disadvantage of urging the spool and in turn the piston sideways or angled from the vertical at the area of detent engagement. Such angulation will cause the wear.
The wear of such a device as the Speedflo unit is greatly increased with the reciprocation of the piston against the cylinder wall and requires frequent servicing.
In addition, the Speedflo hydraulic motor has a tendency to dislodge filters in the area of where the hydraulic fluid moves from the hydraulic motor to the reservoir due to fluid shock at the upward and downward stroke of the piston.
In addition, there is no known bleeder means for hydraulic motors that can be employed to unfreeze such a motor should the piston become frozen due to foreign matter in the fluid.